I'm familiar with distributed applications but brand new to Akka. I understood the discussion (at least in concept) up till listing 2.14. I still understand the concepts but the details in this listing don't seem to gel with the previous discussion.

In particular the Tourist actor gets the Guidebook actor from the 'balancer' config entry. This entry has three guidebook element paths (presumably to the three guidebook processes we start later).

However, there is still a /guidebook entry in the config file with a round-robin-pool router and specifying 5 instances to be created. How do these instances relate to the balancer entry? Are they both needed? If so, why are there 5 in one case and three in the other?